Retinitis pigmentosa 9, also known as RP9 or PAP-1, is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 which in humans is encoded by the RP9 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

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Function

The removal of intron

Intron

An intron is any nucleotide sequence within a gene that is removed by RNA splicing to generate the final mature RNA product of a gene. The term intron refers to both the DNA sequence within a gene, and the corresponding sequence in RNA transcripts. Sequences that are joined together in the final...

s from nuclear pre-mRNAs occurs on a complex called a spliceosome

Spliceosome

A spliceosome is a complex of snRNA and protein subunits that removes introns from a transcribed pre-mRNA segment. This process is generally referred to as splicing.-Composition:...

, which is made up of 4 small nuclear ribonucleoprotein (snRNP

SnRNP

snRNPs , or small nuclear ribonucleoproteins, are RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome, a large RNA-protein molecular complex upon which splicing of pre-mRNA occurs...

) particles and an undefined number of transiently associated splicing factors. The exact role of PAP-1 in splicing is not fully understood, but it is thought that PAP-1 localizes in nuclear speckles containing the splicing factor SC35

SFRS2

Splicing factor, arginine/serine-rich 2 is a protein that in humans is encoded by the SFRS2 gene.-Interactions:SFRS2 has been shown to interact with CDC5L and ASF/SF2.-Further reading:...

 and interacts directly with another splicing factor, U2AF35

U2 small nuclear RNA auxiliary factor 1

Splicing factor U2AF 35 kDa subunit is a protein that in humans is encoded by the U2AF1 gene.-Interactions:U2 small nuclear RNA auxiliary factor 1 has been shown to interact with RP9, U2AF2, NXF1, ASF/SF2 and ZRANB2.-Further reading:...

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Clinical significance

Mutations in PAP1 underlie autosomal dominant retinitis pigmentosa

Retinitis pigmentosa

Retinitis pigmentosa is a group of genetic eye conditions that leads to incurable blindness. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades. Many people with RP do not become legally blind until their 40s or 50s and retain some...

 mapped to the RP9 gene locus

Locus (genetics)

In the fields of genetics and genetic computation, a locus is the specific location of a gene or DNA sequence on a chromosome. A variant of the DNA sequence at a given locus is called an allele. The ordered list of loci known for a particular genome is called a genetic map...

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Interactions

RP9 has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with U2 small nuclear RNA auxiliary factor 1

U2 small nuclear RNA auxiliary factor 1

Splicing factor U2AF 35 kDa subunit is a protein that in humans is encoded by the U2AF1 gene.-Interactions:U2 small nuclear RNA auxiliary factor 1 has been shown to interact with RP9, U2AF2, NXF1, ASF/SF2 and ZRANB2.-Further reading:...

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Further reading